Abstract :
[en] Bee pollen is rich in abundant nutrients, hailed as a treasure trove of human nutrients. This inherent characteristic endows bee pollen with a multifaceted array of functional properties, such as enhancing immunity, helping recovery from chronic illness, slowing aging, antioxidant, and anti-prostatitis. The functional properties of bee pollen, particularly anti-prostatitis, have garnered attention in the realm of pharmaceutical application. The therapeutic attributes of bee pollen are closely associated with its phytochemicals. Rapeseed bee pollen, as a principal medication in China for prostatitis treatment, has been utilized for several years. However, the identification of the specific functional compounds responsible for anti-prostatitis in bee pollen, specifically rapeseed bee pollen, as well as the underlying mechanisms, remains a topic of ongoing research. Furthermore, studies have shown that wall-disruption can increase the availability of nutrients in bee pollen, leading to improved digestibility and absorption. Yet, the effects of wall-disruption on the phytochemicals and anti-prostatitis effects of bee pollen are not well understood. Thus, this dissertation aims to investigate the phytochemical profile of bee pollen, with a focus on identifying the specific compounds in rapeseed bee pollen that contribute to its anti-prostatitis effects and elucidating the underlying mechanisms. This dissertation also examined variations in phytochemicals and anti-prostatitis of rapeseed bee pollen with and without wall-disruption.
Our results indicate that bee pollen is a treasure trove of phenolamides and flavonoid glycosides. The richness in phenolamides and flavonoid glycosides can offer bee pollen more bioactivities as functional foods. The 31 phenolamides and their 33 cis/trans isomers were identified from 20 monofloral bee pollen. In this study, we provided a reliable quantification using prepared phenolamides from bee pollen as standards. In addition, 25 flavonoid glycosides were found in 18 types of bee pollen, including 8 isorhamnetin glycosides, 7 quercetin glycosides, and 6 kaempferol glycosides. To the best of our knowledge, 19 phenolamides and 14 flavonoid glycosides were the first report in bee pollen. Notably in rapeseed bee pollen, 13 phenolamides and their 18 cis/trans isomers are the most abundant among all bee pollen; 9 phenolamides are unique. Additionally, the content of di-p-coumaroyl spermidine in rapeseed bee pollen significantly exceeded levels found in other dietary sources by multiple orders of magnitude.
The results obtained from both in vivo and in vitro studies offer strong evidence supporting the potential anti-prostatitis effects of rapeseed bee pollen, which may be attributed to its abundant phenolamides. Among the eight phenolamides isolated from bee pollen, di-p-coumaroyl spermidine exhibited remarkable efficacy in reducing inflammatory cytokines and nitric oxide levels in cellular models. The elevated concentration of di-p-coumaroyl spermidine within rapeseed bee pollen appears to constitute the primary determinant underlying its heightened efficacy in combating prostatitis relative to alternative varieties of bee pollen. Furthermore, di-p-coumaroyl spermidine can alleviate prostatitis by upregulating autophagy via the AMPK/mTOR signal pathway and modulating gut microbiota. Additionally, our finding may provide a novel insight into the gut-prostate axis through the regulation of di-p-coumaroyl spermidine. This is the first report that di-p-coumaroyl spermidine in bee pollen possesses anti-prostatitis function and its possible mechanism. This finding will be likely helpful further in developing functional foods, personalized nutraceuticals, and medicine from bee pollen.
Wall-disruption promotes the release of phytochemicals within rapeseed bee pollen, resulting in a significant increase in phytochemicals content. Specifically, the content of di-p-coumaroyl spermidine in rapeseed bee pollen with wall-disruption increased by 11%, compared with that non-disruption. Additionally, rapeseed bee pollen can effectively alleviate chronic non-bacterial prostatitis by selectively regulating gut microbiota, with higher doses and wall-disrupted pollen showing greater efficacy. Our results show that rapeseed bee pollen possesses the ability to inhibit pathogenic bacteria and promote probiotics, specifically by decreasing the Firmicutes-to-Bacteroidetes (F/B) ratio and increasing the abundance of Prevotella. This is the first report demonstrating that wall-disruption can enhance the anti-prostatitis effects of rapeseed bee pollen.
Overall, phenolamides, serving as the predominant phytochemicals in bee pollen, confer upon it a multitude of functional properties. The anti-prostatitis effects of rapeseed bee pollen may be mainly attributed to its high content of di-p-coumaroyl spermidine, which alleviates prostatitis through upregulating autophagy via the AMPK/mTOR signal pathway and regulating gut microbiota, suggesting the probable presence of gut-prostate axis. Moreover, wall-disruption facilitates the release of phytochemicals in rapeseed bee pollen, thereby enhancing its anti-prostatitis effects. Therefore, we recommend that rapeseed bee pollen with both the high level of di-p-coumaroyl spermidine and wall-disruption should be selected to target prostatitis as nutraceuticals and therapeutics.
